You can bypass the requirement if the WIFI Does NOT in any way transmit or
connect to PAN data. If the Wireless network does not transmit PAN data and
is segmented from the wired network with VPN FW ACL etc. than your WIFI is
out of scope.

"...11.1 Test for the presence of wireless access points by using a wireless
analyzer at least quarterly or deploying a wireless IDS/IPS to identify all
wireless devices in use..."

I made some research for open source wireless IDSs and results are not good.
I found some articles about using together Kismet and Snort but it looks
like not best soliution.
Air Snort project is dead.
What wireless IDS/IPS (especially opensource/free) do you use?